Lithium salt of branched-aliphatic dicarboxylic acid

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2014-07-30 to 2014-08-18

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Version / remarks:

(July, 2010)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Version / remarks:

(May, 2008)

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

Version / remarks:

(March, 2003)

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Physical state: light yellow powder with lumps (determined at WIL Research Europe B.V.)
- Storage condition of test material: at room temperature in the dark
- Other: pH (1% in water, indicative range) 7.3-7.3 (determined by WIL Research Europe B.V.)

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/J, inbred, SPF-Quality

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Janvier, Le Genest-Saint-Isle, France
- Age at study initiation: Young adult animals (approx. 10 weeks old)
- Weight at study initiation: variation was within +/- 20% of the sex mean.
- Housing: Makrolon cages (MIII type; height 18 cm) containing sterilised sawdust as bedding material (Lignocel S 8-15, JRS - J.Rettenmaier & Söhe GmbH + CO. KG, Rosenberg, Germany). Paper (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom) and shelters (disposable paper corner home, MCORN 404, Datesand Ltd, USA) were supplied as cage-enrichment. On Day 6, the animals were group housed in Makrolon MII type cages with a sheet of paper instead of sawdust and cage enrichment.
- Diet (e.g. ad libitum): pelleted rodent diet (SM R/M-Z from SNIFF^R Spezialdiaten GmbH, Soest, Germany), ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 to 24°C
- Humidity (%): 40 to 70%
- Air changes (per hr): at least 10
- Photoperiod (hrs dark / hrs light): 12-hour light/12-hour dark

Study design: in vivo (LLNA)

Vehicle:

other: Water (Elix, Millipore S.A.S., Molsheim, France) with 1% pluronic L92 (BASF, New Jersey, USA).

Concentration:

10%, 25%, 50% w/w

No. of animals per dose:

five females per group

Details on study design:

RANGE FINDING TESTS:
- Irritation: no irritation determined
- Lymph node proliferation response: not examined

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA
- Criteria used to consider a positive response: if the Stimulation Index (SI) is = 3

TREATMENT PREPARATION AND ADMINISTRATION:
- Days 1, 2, 3: The dorsal surface of both ears was topically treated (25 µL/ear) with the test substance concentration, at approximately the same time on each day. The concentrations were stirred with a magnetic stirrer or mixed with a vortex mixer (main 50% Days 2 and 3) immediately prior to dosing.

Results and discussion

Positive control results:

not performed

In vivo (LLNA)

Results

Results 1

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Mean DPM+-SEM: control: 608+-80 Test item 10%: 407+-78 Test item 25%: 516+-82 Test item 50%: 552+-51

Results 2

Key result

Parameter:

SI

Value:

1

Test group / Remarks:

5 animals/control

Remarks on result:

other: Mean SI+-SEM: control: 1.0+-0.2

Results 3

Key result

Parameter:

SI

Value:

0.7

Test group / Remarks:

5 animals/10% test item

Remarks on result:

other: Mean SI+-SEM: Test item 10%: 0.7+-0.2

Results 4

Key result

Parameter:

SI

Value:

0.8

Test group / Remarks:

5 animals/25% test item

Remarks on result:

other: Mean SI+-SEM: Test item 25%: 0.8+-0.2

Results 5

Key result

Parameter:

SI

Value:

0.9

Test group / Remarks:

5 animals/50% test item

Remarks on result:

other: Mean SI+-SEM: Test item 50%: 0.9+-0.1

Any other information on results incl. tables

Pre-screen test:

No irritation and no signs of systemic toxicity were observed in the animals except for the very slight erythema noted for both animals at 50% on Day 3. Bald spots behind the ears were noted for both animals at 50% from Day 4 onwards. Yellow test substance remnants were present on the dorsal surface of the ears of both animals at 50% (Days 3, 4 and/or 5), which did not hamper scoring of the skin reactions. Variations in ear thickness during the observation period were less than 25% from Day 1 pre-dose values. Based on these results, the highest test substance concentration selected for the main study was a 50% concentration.

Main study:

Skin reactions / Irritation

No irritation of the ears was observed in the animals except for the very slight erythema noted for one animal at 50% (right ear only) on Day 3. Bald spots behind the ears were noted for all animals at 50% from Day 3 onwards. White test substance remnants were present on the dorsal surface of the ears of all animals at 50% (Days 1-3), which did not hamper scoring of the skin reactions.

Systemic toxicity:

No mortality occurred and no clinical signs of systemic toxicity were observed in the animals of the main study. Body weights and body weight gain of experimental animals remained in the same range as controls over the study period.

Macroscopy of the auricular lymph nodes and surrounding area:

All auricular lymph nodes of the animals of the experimental and control groups were considered normal in size. No macroscopic abnormalities of the surrounding area were noted for any of the animals.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Based on the study results, Lithium salt of branched-aliphatic dicarboxylic acid would not be regarded as a skin sensitizer according to the recommendations made in the test guidelines.

Executive summary:

Assessment of Contact Hypersensitivity to Lithium salt of branched-aliphatic dicarboxylic acid in the Mouse (Local Lymph Node Assay).

The study was carried out based on the guidelines described in: OECD, Section 4, Health Effects, No.429 (2010), EC, No 440/2008; B42: "Skin Sensitisation: Local Lymph Node Assay", EPA, OPPTS 870.2600 (2003) “Skin Sensitisation”.

Test substance concentrations selected for the main study were based on the results of a pre-screen test.

In the main study, three experimental groups of five female CBA/J mice were treated with test substance concentrations of 10, 25 or 50% w/w on three consecutive days, by open application on the ears. Five vehicle control animals were similarly treated, but with vehicle alone (water (Elix) with 1% pluronic L92).

Three days after the last exposure, all animals were injected with 3H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised and pooled for each animal. After precipitating the DNA of the lymph node cells, radioactivity measurements were performed. The activity was expressed as the number of Disintegrations Per Minute (DPM) and a stimulation index (SI) was subsequently calculated for each group.

No irritation of the ears was observed in the animals except for the very slight erythema noted for one animal at 50% (right ear only) on Day 3. Bald spots behind the ears were noted for all animals at 50% from Day 3 onwards.

All auricular lymph nodes of the animals of the experimental and control groups were considered normal in size. No macroscopic abnormalities of the surrounding area were noted for any of the animals.

Mean DPM/animal values for the experimental groups treated with test substance concentrations 10, 25 and 50% were 407, 516 and 552 DPM, respectively. The mean DPM/animal value for the vehicle control group was 608 DPM. The SI values calculated for the substance concentrations 10, 25 and 50% were 0.7, 0.8 and 0.9, respectively.

Since there was no indication that the test substance elicited a SI = 3 when tested up to 50%, Lithium salt of branched-aliphatic dicarboxylic acid was not considered to be a skin sensitiser.

The six-month reliability check with Alpha-hexylcinnamaldehyde indicates that the Local Lymph Node Assay as performed at WIL Research Europe is an appropriate model for testing for contact hypersensitivity.

Based on these results, Lithium salt of branched-aliphatic dicarboxylic acid would not be regarded as a skin sensitiser according to the recommendations made in the test guidelines. The test substance does not have to be classified for sensitisation by skin contact according to the Globally Harmonised System of Classification and Labelling of Chemicals (GHS) of the United Nations (2011) (including all amendments) and the Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures (including all amendments).